Brain slice, electrophysiology

Glutamate Rat Cortex (brain slice) Electrophysiology (patch clamp) Vesicle release machinery inhibited Auclair etal. 2000... 

Kohhng, R., Melani, R., and Koch, U. et al. (2005). Detection of electrophysiological indicators of neurotoxicity in human and rat brain slices by a three dimensional microelectrode array. ATLA 33, 579-589. 

A variety of different types of tissue preparation are used to study neurosecretion and synaptic transmission. A classical preparation is the frog NMJ (discussed below). The brain slice has been used for many years for biochemical studies of CNS metabolism and is a useful preparation for electrophysiological studies of synaptic transmission in the CNS. Slices can be oriented to maintain the local neuronal circuitry and can be thin, 0.3 mm, to minimize anoxia. The transverse hippocampal slice is widely used as an electrophysiological preparation to study synaptic plasticity (see Ch. 53). Primary cultures of neurons from selected CNS areas and sympathetic ganglia are also frequently used. They permit excellent visual identification of individual neurons and control of the extracellular milieu, but the normal neuronal connections are disrupted. 

VanderMaelen, C. P., and Aghajanian, G. K. (1983) Electrophysiological and pharmacological characterization of serotonergic dorsal raphe neurons recorded extracellularly and intracellularly in rat brain slices. Brain Res. (in press). 

Only few direct electrophysiological reports of TMS effects on neural activity exist. Effects of TMS on both inhibition and stimulation of neurons are based on indirect electromyographic studies (Ferbert et al. 1992 Pascual-Leone et al. 1994 Valls-Sole et al. 1992 Valzania et al. 1994]. For better comprehension of the neural basis of TMS effects on rat behavior, it is useful to study the effects of the magnetic stimulation on activity of neurons. In this chapter, we report that rapid TMS affects rat behavioral models for ECT. We used rat brain slices for comparison of the behavioral effects with direct effects of rapid TMS on neurons. Some of the above behavioral studies (Fleischmann et al. 1994, 1995] have been reported elsewhere in partial form. 

Table 1. Location of H3 heteroreceptors inhibiting the release of monoamines, acetylcholine and glutamate in the brain. To prove or disprove the presynaptic location of H3 receptors, transmitter release was studied in isolated nerve endings (synaptosomes) or in brain slices superfused with K+-rich Ca2+-free medium containing tetrodotoxin (TTX) (in the latter case, transmitter release was evoked by introduction of Ca2+ ions into the medium). The experimental approaches used in the electrophysiological study to show the presynaptic location of H3 receptors on glutamatergic neurones are described in the text.

Studies on the effects of OPs/CMs have been performed with various preparations, including brain slices, cultured neurons, acutely isolated neurons, iieuroreceptors expressed in a host cell, and neuronal cell lines. The electrophysiologi-cal techniques utilized are extracellular recording, intracellular recording, and patch clamp. Similar to the studies of neuromuscular functions, various compounds were tested. Thus, it i.s extremely difficult to obtain a unified picture regarding the mechani,sm of action of OPs/CMs on. synaptic transmission. 

As mentioned above, there have been two independent research flows concerning endocarmabinoid-induced neuromodulation. One involves biochemical and pharmacological studies on endocarmabinoids and carmabinoid receptors, the other electrophysiological studies on DSl and DSE using brain slices and dissociated neurons. Now, these two flows have merged to provide a promising novel research field. 

Sawant, PM. et al.. Differential effects of domoic acid and its isomers on electrophysiological profiles in CAl hippocampal brain slices and on seizures in the whole animal model. Proc. Ann. Meeting of the Soc. Neurosci., abstract 424.4, Atlanta, 2006. 

Key Words Electrophysiology brain slice marijuana drugs of abuse intracellular extracellular hippocampus synaptic transmission. 

The development of in vitro brain slice and isolated neuron techniques has greatly facilitated detailed studies of the electrophysiology of a wide range of neuronal types in the adult and neonatal vertebrate central nervous system (CNS). Particularly advantageous are the greater mechanical stability that these preparations provide over in vivo models and the control allowed over the composition of the extracellular environment. In addition, the development of the patch-clamp technique has opened up the possibility of direct access to the intracellular environment via internal patch pipet solutions. In combination, these approaches have enabled detailed investigations of neuronal membrane properties, the cellular actions of neurotransmitters, and synaptic mechanisms. 

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